CentOS - Feb 2020 - Switching from lokkit (iptables) to firewalld

Hi All,

Over the last 20 some years I have a file with about 200K worth of address
that have "wrongly" tried to connect to my boxes running centos.  So
the
file has one line per address or group of addresses like:
2.244.112.0/24

So using the OLD iptables I would run through my file build the
iptables.txt file and start that with DROP for the IP address. iptables ran
through the big list in no time.

I was trying to run a script to go through each line and run:
 firewall-cmd --zone=drop --add-source="$ipblock" --permanent
but this takes a long time.

What is a "better" way or more efficient way to keep my long list of
bad
addresses and apply them?  Thanks,

Jerry

On Tue, Feb 4, 2020 at 5:34 AM Jerry Geis <jerry.geis at gmail.com> wrote:
> Hi All,
>
> Over the last 20 some years I have a file with about 200K worth of address
> that have "wrongly" tried to connect to my boxes running centos. 
So the
> file has one line per address or group of addresses like:
> 2.244.112.0/24
>
> So using the OLD iptables I would run through my file build the
> iptables.txt file and start that with DROP for the IP address. iptables ran
> through the big list in no time.
>
> I was trying to run a script to go through each line and run:
>  firewall-cmd --zone=drop --add-source="$ipblock" --permanent
> but this takes a long time.
>
> What is a "better" way or more efficient way to keep my long list
of bad
> addresses and apply them?  Thanks,
>
> Jerry
>
Hi,

If you are using CentOS 7, you can use ipset.

You can add all your IPs and IP ranges to an ipset and do operations on it.

https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/security_guide/sec-setting_and_controlling_ip_sets_using_firewalld

The same should have worked for CentOS 8 except for this,

https://bugzilla.redhat.com/show_bug.cgi?id=1774742

---
Lee

On Mon, 2020-02-03 at 19:04 -0500, Jerry Geis wrote:
> Hi All,
> 
> Over the last 20 some years I have a file with about 200K worth of address
> that have "wrongly" tried to connect to my boxes running centos. 
So the
> file has one line per address or group of addresses like:
> 2.244.112.0/24
> 
> So using the OLD iptables I would run through my file build the
> iptables.txt file and start that with DROP for the IP address. iptables ran
> through the big list in no time.
> 
> I was trying to run a script to go through each line and run:
>  firewall-cmd --zone=drop --add-source="$ipblock" --permanent
> but this takes a long time.
> 
> What is a "better" way or more efficient way to keep my long list
of bad
> addresses and apply them?  Thanks,
> 
To some extent you need to ask yourself if a 20 year old blacklist is
really effective these days. Lots will have changed in that time and
many of the addresses will have been reassigned.

Also, a 200k lump of addresses will surely slow down the processing of
incoming packets?

Perhaps it's time to rethink what you do. Can you define what addresses
would "rightly" try and connect to your machine and whitelist those on
a normally closed system (rather than blacklisting those on a normally
open system).

If you need the system to be open, then I find Fail2Ban useful in
blacklisting addresses that are being naughty. 

P.

On Tue, 4 Feb 2020 at 05:37, Pete Biggs <pete at biggs.org.uk> wrote:
> On Mon, 2020-02-03 at 19:04 -0500, Jerry Geis wrote:
> > Hi All,
> >
> > Over the last 20 some years I have a file with about 200K worth of
> address
> > that have "wrongly" tried to connect to my boxes running
centos.  So the
> > file has one line per address or group of addresses like:
> > 2.244.112.0/24
> >
> > So using the OLD iptables I would run through my file build the
> > iptables.txt file and start that with DROP for the IP address.
iptables
> ran
> > through the big list in no time.
> >
> > I was trying to run a script to go through each line and run:
> >  firewall-cmd --zone=drop --add-source="$ipblock"
--permanent
> > but this takes a long time.
> >
> > What is a "better" way or more efficient way to keep my long
list of bad
> > addresses and apply them?  Thanks,
> >
>
> To some extent you need to ask yourself if a 20 year old blacklist is
> really effective these days. Lots will have changed in that time and
> many of the addresses will have been reassigned.
>
> Also, a 200k lump of addresses will surely slow down the processing of
> incoming packets?
>
>
It will because it is a linear list that every packet has to be 'judged'
against. Even if you break it down to 2 or 3 trees it will still take a
while.

Any list of ip addresses is going to be outdated by a year because of how
ranges are so dynamic these days. Most 'bad-guys' can jump around a
couple
hundred thousand or million ip addresses without much cost on their part
and can get new ranges to screw around weekly.


> Perhaps it's time to rethink what you do. Can you define what addresses
> would "rightly" try and connect to your machine and whitelist
those on
> a normally closed system (rather than blacklisting those on a normally
> open system).
>
> If you need the system to be open, then I find Fail2Ban useful in
> blacklisting addresses that are being naughty.
>
> P.
>
>
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>

-- 
Stephen J Smoogen.